1. Field of the Invention
The present invention relates to a cable stripper of the type used to remove the outer insulation layer of a coaxial cable such as that typically used in the telecommunications industry, and for trimming the stripped distal end of the cable, thereby preparing the stripped cabled for use. The cable stripper of this invention is particularly characterized by its construction including at least one cable stop operatively mounted on the stripper for positively engaging the outer conductor, once the insulation has been removed, so as to provide a stripped cabled segment of predetermined length such that connectors and/or splices applied to the stripped cable distal end will fit properly to ensure proper functionality of the cable.
2. Description of the Prior Art
In the telecommunications industry, relatively large diameter coaxial cables are typically used for transmitting signals from antenna towers to switching equipment. These cables have an outer insulation layer, an outer conductor that is typically formed from copper and has a ridged surface, a layer of foam-type insulation, and an inner conductor, also typically formed from copper. In order to make connections to the cable, it is necessary to remove the outer insulation, and to trim the stripped distal end of the cable. This stripping and trimming operation is critical in at least three regards. First, depending upon the connection being made, a very precise segment of the outer insulation must be removed so as to provide an exposed outer conductor at the cable""s distal end having a predetermined longitudinal dimension. Second, the exposed surface of the outer conductor must not be scratched, bent, nor otherwise marred, for this could result in an improper, non-functional connection being made. Third, the distal end of the stripped cable must be trimmed so that it defines a plane that is substantially normal with respect to the axis of the cable to ensure proper, functional attachment of connecting devices.
While a wide variety of cable stripping devices are known in the prior art, the majority of such prior art devices are constructed merely to remove an outer insulation layer from a conductor. This is true with regard to single conductors and coaxial conductors. Such prior art devices sometimes remove the outer insulation layer by making a longitudinal slit, and others dispose a blade tangentially to remove the outer insulation in a spiral as the cutting device is rotated about the conductor. In most prior art devices, if the distal end of the stripped conductor is to be trimmed, it is frequently necessary to reposition either the cutting device or the stripped cable before trimming the distal end.
In light of the development of relatively large diameter coaxial cables such as those used in the telecommunications industry and generally described above, cable stripping devices for removing the outer insulation layer and for trimming the stripped distal end have been developed. Such devices basically take the form of a cylinder having a passageway through the axis for insertion of the cable to be stripped. In such prior art devices, the cable first encounters a tangential blade that will remove the outer insulation layer as the device is rotated around the cable. The outer insulation is removed as a spiral, and the stripped cable end advances into the stripper. When sufficient outer insulation has been removed the stripped distal end will encounter a second cutting blade that is disposed to trim the stripped distal end to define a plane that is substantially normal to the longitudinal axis of the stripped cable. However, if the operator of the cable stripper continues to rotate the device, more and more outer insulation will be removed, and a corresponding excess of stripped distal end will also be removed. Obviously, this can, over time, result in significant waste of relatively expensive coaxial cable.
The above problem is a result of the fact that prior art devices simply do not provide suitable means for stopping the advancement of cable into the stripper once a predetermined length of the outer insulation layer has been removed. Obviously, the length of exposed outer conductor is predetermined by the distance between the first cutting blade and the second cutting blade. However, there simply is no effective means for stopping the cable stripper once the predetermined segment of outer insulation has been removed.
It is therefore apparent that there remains a great need in the art for a cable stripper suitable for use in combination with coaxial cables for removing the outer insulation and for trimming the stripped distal end, and for positively stopping the stripping action once a predetermined segment of outer conductor has been has been exposed. In addition, any such means for stopping further advancement of the cable once the predetermined segment has been exposed must not damage the outer conductor, or subsequent failure of the cable for its intended purpose could occur.
The present invention relates to a cable stripper for removing the external or outer layer of insulation on a coaxial cable having a ridged outer conductor and an inner conductor, the two conductors being separated by insulation. The cable stripper further includes means for trimming the stripped cable end to define a plane that is substantially normal to the longitudinal dimension of the stripped cable. The cable stripper of this invention is preferably a substantially cylindrical housing having a central bore for receiving the cable to be stripped. This bore or passageway is dimensioned and configured to receive the cable and a first blade is mounted on the housing in operative communication with the passageway whereby the first blade will remove the outer layer of insulation from the cable as either the stripper is rotated, or the cable is rotated. As stripped cable advances into the passageway, the stripped distal end engages a cable shoulder formed on at least one cable stop that is pivotally attached to the housing, causing the cable stop to pivot outwardly.
Disposed at the bottom of this cable stop is a lock tip that necessarily pivots inwardly, toward the stripped cable. Mounted below the cable stop is a retaining member that is biased into engagement with the bottom of its corresponding cable stop. This bearing surface defines a first planer segment that abuts a corresponding stop member bottom surface, and the bearing surface then defines a second angled surface that will engage the backside of its corresponding cable stop when it has pivoted sufficiently to clear the first planer segment. Because the retaining member is normally biased toward its corresponding cable stop bottom surface, as the stop pivots beyond the retaining member first planer segment onto the second angled surface, the biasing action will effectively lock the lock tip into a corresponding groove of the ridged outer conductor. This positively prevents further advancement of the cable into the stripper, resulting in a stripped distal end having a longitudinal dimension defined by the predetermined distance between the first and second blades of the stripper and prevents waste of the conductor. Depending upon the size (diameter) of the cable, a plurality of cable stops and, thus, a corresponding plurality of retaining members may be utilized for preventing further advancement of the cable.
The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the preferred construction hereinafter set forth, and the scope of the invention will be indicated in the claims.